Dental engine handpiece



Sept 29, 1953 w. P. UHLER DENTAL ENGINE. HANDPIECE f l/////// A N /V////.//JV//////////////////,/.

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Filed Sept. 3, 1949 Patented Sept. 29, 1953 UNITED STATES PATENT OFFICE 2,653,383 DENTAL ENGINE HANDPIECE Wilmer P. Uhler, Tottenville, N. Y., assignor to The S. S. White Dental Manufacturing Company, a corporation of Pennsylvania Application September 3, 1949, Serial No. 114,002

Claims. -1

My invention relates particularly to that class of handpieces that are adapted to be employed in connection with dental engines and in which the rotating parts include chuck mechanism that is arranged to detachably `engage drills, burs, discs, and such other implements as are commonly employed in the practice of dentistry, and in which the tool actuating parts are belt driven and the assembly is generally known as an all cord handpiece.

The principal objects of my invention are to provide a dental engine handpiece in which the several parts are so cooperatively formed as to lend themselves to such a convenient relatively interengaged assemblage as will afford a considerable curtailment of the expense in the ultimate production of the assembled structure.

Other objects of my invention are to provide .a dental engine handpiece in which the spindle and sheath may be conveniently removed for purpose of sterilization and adjustment and replaced without displacing the driving belt from the spindle driving pulley.

Further objects of my invention are to provide means to prevent, while not in use, any rotation or so called spinning of the handpiece casing or sheath which may be incident to the torque exerted between the relatively rotative parts of the running engine and the handpiece while hanging idle.

My invention comprehends such novel features of procedure in the manufacture of the parts of thev handpiece as to eliminate soldering, brazing or other heat treatment processes as may tend to expand or distort the structure in its process of production.

The form of my invention as hereinafter more 'specifically described comprises a dental engine handpiece in which its nosepiece andknurled casing are swaged together to form the sheath which is removably engaged by 4a union nut with the wrist-joint frame through which an' elongated rear bearing for the tubular tool actuating spindle is threadedly engaged for axial adjustment of the swaged forward `conoidal end portion of said spindle with respect to its forward bearing in the aforesaid nosepiece, said elongatedrbearing being rearwardly cupped and outwardlyV knurled to aiord a thumb knob, which not only serves to catch excess oil dripping from the driving pulley, but also serves to support said pulley when theV handpiece parts, including the spindle, are withdrawn for sterilizing purposes.

yMy invention also includes all of the various novel features of construction and arrangement as hereinafter more definitely specied in detail.

In the accompanying drawing, Figure 1 is a side elevational view of a handpiece constructed in accordance with my invention; Fig. 2 is an enlarged central vertical longitudinal sectional view showing the internal structure of the handpiece illustrated in Fig. l, certain parts being shown in elevation, and the wrist-joint structure being omitted for convenience of illustration; Fig. 3 is an enlarged fragmentary central vertical longitudinal sectional View of the forward end portion of the handpiece sheath or casing, illustrating the annular internal groove into 'which the inner end of the nosepiece may be swaged and thereby expanded into interlocked integral relation; Fig. 4 is an enlarged central vertical longitudinal sectional view of th-e nosepiece in the form arranged to be inserted into the bore of the forward fragment of the handpiece casing shown in Fig. 3; Fig. 5 is a fragmentary rear end vertical sectional View of the handpiece illustrated in Fig. 2, modied by providing for the insertion of a,V spring friction washer designed to prevent undesirable rotation of the handpiece `casing when 4hanging idle; Fig. 6 is a front elevational view of said washer; and Fig. 7 is a transverse vertical sectional view of said washer taken on the line 'i in. Fig. 6.

In said gures, the wrist-joint frame l is provided with the hollow supporting swivel post 2, which is swivelly engaged with the wrist-joint structure 3 of well known construction.

The wrist-joint frame is provided with the supporting hub i which is engaged therein by its swaged rearwardly disposed flange 5 and which is provided with the radially directed flange E and has the screw threaded bore i through which the elongated spindle bearing 's exten-ds in threaded engagement therewith for axial adjustments.

Said spindle bearing al is formed at its inner end with a cupped enlargement il terminating in an inturned ilange it and having its outer cylindrical surface provided with iznurling i 2 to facilitate the axial adjust. 'lent of said spindle bearing 3 through its supporting hub s, and in which adjusted position it may be retained by the spindle bearing retaining nut i3, as best illustrated in Fig. 2.

The handpiece sheath comprising the nosepiece i5 and tubular linux-led casing le which has the radially directed terminal flange il, is removably supported by and engaged with the screw threaded ange 8 of the supporting hub 4 by the union nut I9 embracing said flange Il, as shown in Fig. 2.

The spindle 2e extends throughout the handpiece and is formed of tub-ing of one piece, the forward end portion of which is swaged inwardly to provide the-cone bearing which conforms to the cone bearing 22 in the bore o-f the nosepiece I5, and said spindle is supported in the longitudinally adjustable bearing 8 from which it projects rearwardly to receive the drivingv pulley 2.3.

As shown in Fig. 2, the spindle 2o is provided near its middle region with theielongatedfbearing collar 25, which encircles said.v spindle andV bears at its inner end 26 against the outer end 2`l''of the bearing '8, whereby axial adjustment of saidbearing 8 tends to vary the relation between the conical bearing surfaces of said spindle and' nose-- piece.

In order to prevent distortion of the spindle 2li:

incident to attaching. the collar 25 bythe process of soldering or bracing, and to provide a true and smooth bearing, the rearward third: portion, approximately, of said spindle is gro-und or otherwise slightly reduced to a region intermediate of the ends of said collar .c when in the position shown.

Said collar 25 having been made to approxi-v mately slip fit the slightly Vreduced portion of the spindle 2o is forced axially forward over said slightly reduced region until it encounters the unreduced region of said spindle whereupon relatively higher forces may advance it forwardly to integrally engage said spindle with its bearing edge 2e at a predetermined relation with respect to the conical bearing 22 in the nosep-iece l5.

The spindle 2t terminates rearwardly inY a reduced axially extended flange 2'! which has diametrically disposed-notches '23, see Fig. 5, to repectively receive the diametricallyY disposed key projections il@ llon the driving pulleyv 23 which is maintained in removable engagement on said by the chuck-rod collet 3l whose stem 32 e :lds into the rear end of said spindle ink threaded engagement therewith.

The chuck rod 33 extends forwardly through the spindle 2c being` provided with the collar 35 by which it is maintained centrally located within said spindle and having the screw threads 3l interengaged with screw threads 3S in the bore of the chuck-rod collet Srl and being provided with the knurled knob die by which said chuck rod may'berotated to-effect its-axial advancement or its retraction.

As sho-wn in 2, the forward end of the bore il of the spindle 'Zt is concally tapered toward the axially aligned tool receivi ff aperture cl2 and affords a conical forward seat for the longitudinally split chuck 35 through the bore iii of which the shank iii', of the tool which is illustrated in Fig. l and which comprises the bur head Eil, extends.

The chuck is normally expanded. to loosely receive the tool shank il and hasV its opposite ends formed conical and respectivelyV arranged to engage the conical seat i3 in the bore of the spindle 2e and the conical seat il in the forward end yof the follower E2 which is disposed for axial movement in the bore il of the spindle 2&3 and;

arranged to be forced forward to eifect contrae.-

tion of the chuck by axial adjustment of the chuck rod 33 when rotated bythe knob d.

Asshown in Fig. 2, the hub 55 ofthe driving pulleyy 2.3 is provided with a circumferential:

V-shaped groove 58 which is arranged to arrest any excess lubrication and deposit it into the receptacle formed by the cupped enlargement head 9 of the bearing 8. This V-shaped groove '58 also serves in cooperation with the inturned flange I of the cupped enlargement head 9 of the bearing 8 to arrest and so support the driving pulley 23 as to avoid the necessity of disconnection'of 'the driving lbelt therefrom when the handpiece parts are disassembled for sterilization purposes, a feature that is deemed to be highly desirable in saving the operators time.

In handpieces wherein the sheath has been formed of composite unit-s such as Ithe casing and its connected-nosepiece, it has been the general practice to join them by solder or by brazing, which-,often causes undesirable warping or distortion and tends to throw the thus joined parts out ofv true axial alignment.

In the handpiece as illustrated in Figs. 2, 3 and 4, the separately formed parts oftthe sheath comprising` the casing iliandnosepiece l5. are joined; solelyu by frictionalengagement to form a sturdy integral sheath. structure by swagin'g the, nose.- piece into the casing.

Asfshown` in Figs.t2 and 3, the.v casing IIY is provided with the internal. annularl groove 5l. in itsbore 5B forming anforwardly directed shoulder disposed at a predetermined distance from the forward end BU of said casing I6..

The nosepiece` I5, as'. best'Y shown in.v Fig. 4, is provided.v with a reduced rearwardly projecting cylindrical extensioni II` which forms the annu'- lai` abutment' shoulderA 62,.th'e lengthA of said c xtension 6I being inV excess of the, distance between theV forward end E0' ofthe casing' IB and the shoulder 59 in thebore thereofl The. assembly ofi theV sheathstructure may be readily: elfected by slipping the cylindrical extension 6l of the nosepiece I5 into the bore 58l ofthe casing I until the shoulder B2 of they nosepiece Iii engages the forward end 60' of thev casing IE, as shown in Fig. 2; whereupon the inner end region 63 of said extension' 6I that projects inwardly beyondthe shoulder 59 is spun orstaked by a suitable tool extended through theY bore 56 ofthe casing IB' from the inner endV thereof and thus expanded to formthe annular locking an'ge 65 shown` in Fig. 2, whereby to provide a rigid integral sheath' structure having itsassembled parts in perfectv alignment.

When the spindle 20 is rotatedin the sheath,

some torque may be transmitted to theA sheathv due` to the viscosityr of theoil'lm in the bearings, or possibly due to a slight rnalalignmentY of the spindle bearings, .thus tending to cause the sheath to rotate when thehandpiece is hanging idle while the engine is running.

As, illustrated in Fig. .5, the fragmentary structure depicting the wrist-joint frame I`, the supportingv hub 4, thespindle bearing 8, spindle 201 and spindle bearing nut I3, showsthecasing I6 engaged-in operativev position by the union nut 'hof modified structurawhich is providedwith the slightly undercut annular' pocket' arranged to receive thesplit spring Washer 'I0 which, as best shown inliig.V 6, has its opposed ends II and l2 preferably separated so as tok better lend itself to be inserted into said undercut pocket 69.

As illustrated-in Fig. 7, the-spring washer Illl is. normally,v distorted so that its diametrically opposite upperfandflowerfaces-13.and 'I4 respectively conform to relatively spaced planes and better serve to frictionally engage the opposed plane surfaces of the flange I1 and the spindle bearing supporting hub 4, as shown in Fig. 5.

As will be obvious from an inspection of Fig. 5, the washer 10, by its engagement with the undercut annular shoulder 15, serves to retain the union nut 61 on the casing IB of the handpiece sheath while said sheath is removed for sterilizing purposes.

I do not desire to limit my invention to the precise details of construction and arrangement as herein set forth, as it is obvious that various modifications may be made therein Without departing from the essential features of my invention as defined in the appended claims.

Having thus described my invention, I claim:

1. A dental engine handpiece comprising a sheath, having a forward bearing, va support for said sheath, means arranged to removably engage said sheath with said support, an elongated axially adjustable bearing in said support, a tool driving spindle mounted to rotate in said bearings and having a collar mounted medially thereon and engaged therewith solely by friction and cooperative with the forward end of said elongated bearing to maintain said spindle engaged with said forward bearing, the inner end of said spindle being reduced in diameter to provide an axially extended flange having diametrically opposite notches in its free edge, and a driving pulley mounted on said spindle and having axially projecting keys slidingly engaged in said notches and insuring their contemporaneous rotation.

2. A dental engine handpiece comprising a sheath having a forward bearing, a support for said sheath, means arranged to removably engage the sheath with said support, an axially adjustable bearing threadedly mounted in said support and terminating rearwardly in a cupped adjusting head having an inturned ange and provided with knurling on its outer cylindrical surface to facilitate rotary adjustment of said bearing, a spindle bearing nut arranged to maintain said bearing in any axial adjusted position, a tool actuating spindle mounted to rotate in said bearings and having a collar With which the forward end of said adjustable bearing engages, a belt actuated driving pulley mounted on said spindle and having a forwardly projecting hub provided with an annular groove arranged to direct sur- 6 plus lubricant into said cupped head when the handpiece parts are in operation and to engage the inturned ange of said head and rest thereon with the driving belt intact when the handpiece parts are dissembled for sterilizing or other purposes.

3. A dental engine handpiece comprising a sheath terminating rearwardly in a radially extended ange, a support including a tool driving spindle bearing, a union nut connecting said sheath with said support, and an axially distorted spring Washer effecting axial thrust interposed between said ange and support.

4. A dental engine handpiece comprising a sheath terminating in a transverse surface, a support having a relatively opposed transverse surface, and yielding means comprising an axially distorted washer interposed between said surfaces tending to restrict the relative rotation of said sheath and support, and serving as a retarding brake.

5. A dental engine handpiece comprising a sheath terminating in a transverse annular surface, a support for said sheath having an opposed annular surface and a screw threaded exterior, a union nut in threaded relation therewith and having an annular internal recess arranged to engage said sheath with said support, and a split spring washer interposed between said surfaces and having its peripheral margin extended into said recess, tending to yieldingly exert axial pressure and thereby frictionally retard the relative rotation of said sheath and its support, and serving to retain said union nut engaged with said sheath when separated from its support.

WILMER P. UHLER.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 170,125 Starr Nov. 16, 1875 434,295 Richardi Aug. 12, 1890 869,563 Hardy Oct. 20, 1907 1,655,659 Nicolello Jan. 10, 1928 1,922,644 Terry Aug. 15, 1933 2,432,179 Staunt Dec. 9, 1947 2,538,923 Staunt Jan. 23, 1951 

